Update

Apparently this is patched out by Brave, but it is enabled by default. See u/Engywuck@lemm.ee 's comment below!

Vanilla chromium gives google’s websites special treatment by offering detailed CPU info, among other things. This is implemented through a hidden browser extension. You can prove this by yourself by running chrome.runtime.sendMessage("nkeimhogjdpnpccoofpliimaahmaaome", {method: "cpu.getInfo"}, (response) => {console.log(JSON.stringify(response, null, 2)); }, ); on google.com through the browser console. For me, it gives the following info:

{
  "value": {
    "archName": "x86_64",
    "features": [
      "mmx",
      "sse",
      "sse2",
      "sse3",
      "ssse3",
      "sse4_1",
      "sse4_2",
      "avx"
    ],
    "modelName": "Intel(R) Core(TM) i7-2620M CPU @ 2.70GHz",
    "numOfProcessors": 4,
    "processors": [
      {
        "usage": {
          "idle": 28238205,
          "kernel": 827581,
          "total": 32762960,
          "user": 3697174
        }
      },
      {
        "usage": {
          "idle": 1455131,
          "kernel": 743391,
          "total": 6209241,
          "user": 4010719
        }
      },
      {
        "usage": {
          "idle": 1448653,
          "kernel": 769970,
          "total": 6068506,
          "user": 3849883
        }
      },
      {
        "usage": {
          "idle": 1450274,
          "kernel": 744886,
          "total": 5948597,
          "user": 3753437
        }
      }
    ],
    "temperatures": []
  }
}

Note that this doesn’t work on other websites like lemmy.world, only google.

What I am confused about is that I can replicate this behavior in Brave. Why does brave reveal this information to google, and to google only? From what I understand, it can be used for fingerprinting and tracking. Shouldn’t this be patched out? Is my testing methodology flawed? Will this be fixed?

Brave version: Version 1.67.123 Chromium: 126.0.6478.126 (Official Build) unknown (64-bit) running on linux via flatpak